Delta's response on Sunday came after Coulter had gone on a very long Twitter tirade against the airline for allegedly moving her from her preferred seat without an explanation. During the tirade, she called the customer who was allegedly given her seat a "dachshund-legged woman."

In another tweet, the airline also apologized for moving Coulter from her preferred seat and said it would refund the $30 she paid for the seat.

Delta spokesman Anthony Black told BuzzFeed News that Coulter was moved to a new seat in the same row, so it shouldn't have impacted her leg room. They also said that at the time, Coulter did not ask about the movement or complain.

"At the time, she didn't specifically call it out, she didn't complain about it, she didn't say anything about it," Black told BuzzFeed News. "She didn't say anything the entire flight — not to anyone."

Delta's website says that "seats may be reassigned to passengers with certain categories of disability," but Black told BuzzFeed News that Coulter's seat change was accidental.

"It was inadvertent," Black said, elaborating that the change occurred because a gate agent was trying to seat people together.

Black said Delta hit back at Coulter in their tweet only after it had responded to her on Twitter, through direct message, and by calling her.

He said Delta decided to send the tweet after it felt her insults had escalated and were targeting their crew and customers.

"If you look at her tweets, they go from something very specific to something very general," Black said. "Today's tweets have been ... attacking our people and our employees ... She's basically attacking 80,000 people today versus complaining about a situation that was specific to her."

Delta decided to respond to Coulter because it wanted to stick up for both its employees and its customers.

"Our response ... was to have the backs of our employees as well as to support our customers," Black said.

BuzzFeed News reached out to Coulter for more information, but did not immediately receive a response.

Delta issued the following statement Sunday night in response to Coulter’s insults:

We are sorry that the customer did not receive the seat she reserved and paid for. More importantly, we are disappointed that the customer has chosen to publicly attack our employees and other customers by posting derogatory and slanderous comments and photos in social media. Her actions are unnecessary and unacceptable.

Each of our employees is charged with treating each other as well as our customers with dignity and respect. And we hold each other accountable when that does not happen.